Experimental Optical Performance of a Nonimaging Fresnel Reflective Concentrator for Building Integration Applications
Abstract
A transmissive Fresnel reflector has been constructed to match the needs of building integration for concentrating photovoltaic (PV), thermal (T) or hybrid photovoltaic/thermal (PVT) generation. The device concentrates radiation towards a static receiver, in a manner analogous to a lens, by means of an array of mirrors which rotate collectively. All rotation axes are coplanar and parallel. The system concentrates solar radiation up to 20 suns. The movable parts of the structure are the mirrors. The mechanism to track the Sun has been performed through connecting rods, one in each line of reflectors and another one connected to a single linear driver and to the strips of mirrors. The angular rotation of the mirrors is equal in all of them, and at the same time is the half than the angular movement of the Sun. To transfer this relation a very simple reduction gear is used. The tracking control is done by means of 2 photo resistances and a shadowing plate connected to a Peripheral Interface Controller (PIC) microchip. The research aims to characterize the optical performance of a concentrating system capable of being integrated in buildings adequately.